【国外标准】 Standard Test Method for Shrinkage of Carpet Backing Fabrics

5.1 This test method can be useful in characterizing and comparing shrinkage properties of both primary and secondary backing fabrics. This test method is considered satisfactory for acceptance testing of commercial shipments because current estimates of between-laboratory precision are acceptable, and this test method is commonly used in the trade for acceptance testing.5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is statistical bias between them using competent statistical assistance. As a minimum, use test samples for such comparative tests that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in the disparate results during initial testing, and that are randomly assigned in equal numbers to each laboratory for testing. The test results from the laboratories should be compared using statistical test for unpaired data at a probability level chosen prior to the testing series. If a bias is found either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.1.1 This test method covers the procedure for evaluating shrinkage, in both wet and dry conditions, of woven, knitted and nonwoven backing fabrics designed for use in the manufacture of pile yarn floor coverings. Determination of carpet backing shrinkage was previously contained within Test Methods D2646. For consistency, Subcommittee D13.21 extracted this portion and created a separate test method.1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.